A synthesis of the environmental response of the North and South Atlantic Sub-Tropical Gyres during two decades of AMT

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.Anthropogenically-induced global warming is expected to decrease primary productivity in the subtropical oceans by strengthening stratification of the water column and reducing the flux of nutrients from deep-waters to the sunlit surface layers. Identification of such changes is hindered by a paucity of long-term, spatially-resolved, biological time-series data at the basin scale. This paper exploits Atlantic Meridional Transect (AMT) data on physical and biogeochemical properties (1995–2014) in synergy with a wide range of remote-sensing (RS) observations from ocean colour, Sea Surface Temperature (SST), Sea Surface Salinity (SSS) and altimetry (surface currents), combined with different modelling approaches (both empirical and a coupled 1-D Ecosystem model), to produce a synthesis of the seasonal functioning of the North and South Atlantic Sub-Tropical Gyres (STGs), and assess their response to longer-term changes in climate. We explore definitive characteristics of the STGs using data of physical (SST, SSS and peripheral current systems) and biogeochemical variables (chlorophyll and nitrate), with inherent criteria (permanent thermal stratification and oligotrophy), and define the gyre boundary from a sharp gradient in these physical and biogeochemical properties. From RS data, the seasonal cycles for the period 1998–2012 show significant relationships between physical properties (SST and PAR) and gyre area. In contrast to expectations, the surface layer chlorophyll concentration from RS data (CHL) shows an upward trend for the mean values in both subtropical gyres. Furthermore, trends in physical properties (SST, PAR, gyre area) differ between the North and South STGs, suggesting the processes responsible for an upward trend in CHL may vary between gyres. There are significant anomalies in CHL and SST that are associated with El Niño events. These conclusions are drawn cautiously considering the short length of the time-series (1998–2012), emphasising the need to sustain spatially-extensive surveys such as AMT and integrate such observations with models, autonomous observations and RS data, to help address fundamental questions about how our planet is responding to climate change. A small number of dedicated AMT cruises in the keystone months of January and July would complement our understanding of seasonal cycles in the STGs.Natural Environment Research Council National CapabilityUK National Centre for Earth Observatio

Galaxy And Mass Assembly (GAMA): mass-size relations of z < 0.1 galaxies subdivided by Sersic index, colour and morphology

We use data from the Galaxy And Mass Assembly (GAMA) survey in the redshift range 0.01 < z < 0.1 (8399 galaxies in g to Ks bands) to derive the stellar mass–half-light radius relations for various divisions of ‘early’- and ‘late’-type samples. We find that the choice of division between early and late (i.e. colour, shape, morphology) is not particularly critical; however, the adopted mass limits and sample selections (i.e. the careful rejection of outliers and use of robust fitting methods) are important. In particular, we note that for samples extending to low stellar mass limits (<10 10 M ⊙ ) the Sérsic index bimodality, evident for high-mass systems, becomes less distinct and no-longer acts as a reliable separator of early- and late-type systems. The final set of stellar mass–half-light radius relations are reported for a variety of galaxy population subsets in 10 bands (ugrizZY JHKs) and are intended to provide a comprehensive low-z benchmark for the many ongoing high-z studies. Exploring the variation of the stellar mass–half-light radius relations with wavelength, we confirm earlier findings that galaxies appear more compact at longer wavelengths albeit at a smaller level than previously noted: at 10 10 M ⊙ both spiral systems and ellipticals show a decrease in size of 13 per cent from g to Ks (which is near linear in log wavelength). Finally, we note that the sizes used in this work are derived from 2D Sérsic light profile fitting (using galfit3), i.e. elliptical semimajor half-light radii, improving on earlier low-z benchmarks based on circular apertures

Galaxy And Mass Assembly (GAMA): mass-size relations of z < 0.1 galaxies subdivided by Sersic index, colour and morphology

We use data from the Galaxy And Mass Assembly (GAMA) survey in the redshift range 0.01 < z < 0.1 (8399 galaxies in g to Ks bands) to derive the stellar mass–half-light radius relations for various divisions of ‘early’- and ‘late’-type samples. We find that the choice of division between early and late (i.e. colour, shape, morphology) is not particularly critical; however, the adopted mass limits and sample selections (i.e. the careful rejection of outliers and use of robust fitting methods) are important. In particular, we note that for samples extending to low stellar mass limits (<10 10 M ⊙ ) the Sérsic index bimodality, evident for high-mass systems, becomes less distinct and no-longer acts as a reliable separator of early- and late-type systems. The final set of stellar mass–half-light radius relations are reported for a variety of galaxy population subsets in 10 bands (ugrizZY JHKs) and are intended to provide a comprehensive low-z benchmark for the many ongoing high-z studies. Exploring the variation of the stellar mass–half-light radius relations with wavelength, we confirm earlier findings that galaxies appear more compact at longer wavelengths albeit at a smaller level than previously noted: at 10 10 M ⊙ both spiral systems and ellipticals show a decrease in size of 13 per cent from g to Ks (which is near linear in log wavelength). Finally, we note that the sizes used in this work are derived from 2D Sérsic light profile fitting (using galfit3), i.e. elliptical semimajor half-light radii, improving on earlier low-z benchmarks based on circular apertures

Galaxy and mass assembly: the G02 field, Herschel–ATLAS target selection and data release 3

We describe data release 3 (DR3) of the Galaxy And Mass Assembly (GAMA) survey. The GAMA survey is a spectroscopic redshift and multiwavelength photometric survey in three equatorial regions each of 60.0 deg2 (G09, G12, and G15), and two southern regions of 55.7 deg2 (G02) and 50.6 deg2 (G23). DR3 consists of: the first release of data covering the G02 region and of data on H-ATLAS (Herschel – Astrophysical Terahertz Large Area Survey) sources in the equatorial regions; and updates to data on sources released in DR2. DR3 includes 154 809 sources with secure redshifts across four regions. A subset of the G02 region is 95.5 per cent redshift complete to r < 19.8 mag over an area of 19.5 deg2, with 20 086 galaxy redshifts, that overlaps substantially with the XXL survey (X-ray) and VIPERS (redshift survey). In the equatorial regions, the main survey has even higher completeness (98.5 per cent), and spectra for about 75 per cent of H-ATLAS filler targets were also obtained. This filler sample extends spectroscopic redshifts, for probable optical counterparts to HATLAS submillimetre sources, to 0.8 mag deeper (r < 20.6 mag) than the GAMA main survey. There are 25 814 galaxy redshifts for H-ATLAS sources from the GAMA main or filler surveys. GAMA DR3 is available at the survey website (www.gama-survey.org/dr3/)

Telomerase and breast cancer

Current therapies for breast cancer include treatments that are toxic and often result in drug resistance. Telomerase, a cellular reverse transcriptase that maintains the ends of chromosomes (telomeres), is activated in the vast majority of breast cancers (over 90% of breast carcinomas) but not in normal adjacent tissues. Telomerase is thus an attractive target for both diagnosis and therapy because of its distinct pattern of expression. We address the use of telomerase in the diagnostics of breast pathology, as well as the use of telomerase inhibitors in the treatment and prevention of breast cancer

Galaxy And Mass Assembly (GAMA): the effect of close interactions on star formation in galaxies

The modification of star formation (SF) in galaxy interactions is a complex process, with SF observed to be both enhanced in major mergers and suppressed in minor pair interactions. Such changes likely to arise on short timescales and be directly related to the galaxy-galaxy interaction time. Here we investigate the link between dynamical phase and direct measures of SF on different timescales for pair galaxies, targeting numerous star-formation rate (SFR) indicators and comparing to pair separation, individual galaxy mass and pair mass ratio. We split our sample into the higher (primary) and lower (secondary) mass galaxies in each pair and find that SF is indeed enhanced in all primary galaxies but suppressed in secondaries of minor mergers. We find that changes in SF of primaries is consistent in both major and minor mergers, suggesting that SF in the more massive galaxy is agnostic to pair mass ratio. We also find that SF is enhanced/suppressed more strongly for short-time duration SFR indicators (e.g. H-alpha), highlighting recent changes to SF in these galaxies, which are likely to be induced by the interaction. We propose a scenario where the lower mass galaxy has its SF suppressed by gas heating or stripping, while the higher mass galaxy has its SF enhanced, potentially by tidal gas turbulence and shocks. This is consistent with the seemingly contradictory observations for both SF suppression and enhancement in close pairs

Galaxy And Mass Assembly (GAMA): the effect of close interactions on star formation in galaxies

The modification of star formation (SF) in galaxy interactions is a complex process, with SF observed to be both enhanced in major mergers and suppressed in minor pair interactions. Such changes likely to arise on short timescales and be directly related to the galaxy-galaxy interaction time. Here we investigate the link between dynamical phase and direct measures of SF on different timescales for pair galaxies, targeting numerous star-formation rate (SFR) indicators and comparing to pair separation, individual galaxy mass and pair mass ratio. We split our sample into the higher (primary) and lower (secondary) mass galaxies in each pair and find that SF is indeed enhanced in all primary galaxies but suppressed in secondaries of minor mergers. We find that changes in SF of primaries is consistent in both major and minor mergers, suggesting that SF in the more massive galaxy is agnostic to pair mass ratio. We also find that SF is enhanced/suppressed more strongly for short-time duration SFR indicators (e.g. H-alpha), highlighting recent changes to SF in these galaxies, which are likely to be induced by the interaction. We propose a scenario where the lower mass galaxy has its SF suppressed by gas heating or stripping, while the higher mass galaxy has its SF enhanced, potentially by tidal gas turbulence and shocks. This is consistent with the seemingly contradictory observations for both SF suppression and enhancement in close pairs

Galaxy And Mass Assembly (GAMA): galaxy close pairs, mergers and the future fate of stellar mass

We use a highly complete subset of the Galaxy And Mass Assembly II (GAMA-II) redshift sample to fully describe the stellar mass dependence of close pairs and mergers between 10(8) and 10(12)M(circle dot). Using the analytic form of this fit we investigate the total stellar mass accreting on to more massive galaxies across all mass ratios. Depending on how conservatively we select our robust merging systems, the fraction of mass merging on to more massive companions is 2.0-5.6 per cent. Using the GAMA-II data we see no significant evidence for a change in the close pair fraction between redshift z = 0.05 and 0.2. However, we find a systematically higher fraction of galaxies in similar mass close pairs compared to published results over a similar redshift baseline. Using a compendium of data and the function gamma(M) = A(1 + z)(m) to predict the major close pair fraction, we find fitting parameters of A = 0.021 +/- 0.001 and m = 1.53 +/- 0.08, which represents a higher low-redshift normalization and shallower power-law slope than recent literature values. We find that the relative importance of in situ star formation versus galaxy merging is inversely correlated, with star formation dominating the addition of stellar material below M* and merger accretion events dominating beyond M*. We find mergers have a measurable impact on the whole extent of the galaxy stellar mass function (GSMF), manifest as a deepening of the &#39;dip&#39; in the GSMF over the next similar to Gyr and an increase in M* by as much as 0.01-0.05 dex.</p

Galaxy And Mass Assembly (GAMA): the G02 field, Herschel-ATLAS target selection and Data Release 3

We describe data release 3 (DR3) of the Galaxy And Mass Assembly (GAMA) survey. The GAMA survey is a spectroscopic redshift and multi-wavelength photometric survey in three equatorial regions each of 60.0 deg^2 (G09, G12, G15), and two southern regions of 55.7 deg^2 (G02) and 50.6 deg^2 (G23). DR3 consists of: the first release of data covering the G02 region and of data on H-ATLAS sources in the equatorial regions; and updates to data on sources released in DR2. DR3 includes 154809 sources with secure redshifts across four regions. A subset of the G02 region is 95.5% redshift complete to r<19.8 over an area of 19.5 deg^2, with 20086 galaxy redshifts, that overlaps substantially with the XXL survey (X-ray) and VIPERS (redshift survey). In the equatorial regions, the main survey has even higher completeness (98.5%), and spectra for about 75% of H-ATLAS filler targets were also obtained. This filler sample extends spectroscopic redshifts, for probable optical counterparts to H-ATLAS sub-mm sources, to 0.8 mag deeper (r<20.6) than the GAMA main survey. There are 25814 galaxy redshifts for H-ATLAS sources from the GAMA main or filler surveys. GAMA DR3 is available at the survey website (www.gama-survey.org/dr3/)

Galaxy And Mass Assembly (GAMA): galaxy close pairs, mergers and the future fate of stellar mass

We use a highly complete subset of the GAMA-II redshift sample to fully describe the stellar mass dependence of close-pairs and mergers between 108M_ and 1012M_. Using the analytic form of this fit we investigate the total stellar mass accreting onto more massive galaxies across all mass ratios. Depending on how conservatively we select our robust merging systems, the fraction of mass merging onto more massive companions is 2:0%{5:6%. Using the GAMA-II data we see no significant evidence for a change in the close-pair fraction between redshift z = 0:05{0:2. However, we find a systematically higher fraction of galaxies in similar mass close-pairs compared to published results over a similar redshift baseline. Using a compendium of data and the function M = A(1+z)m to predict the major close-pair fraction, we find fitting parameters of A = 0:021 _ 0:001 and m = 1:53 _ 0:08, which represents a higher low-redshift normalisation and shallower power-law slope than recent literature values.We find that the relative importance of in-situ star-formation versus galaxy merging is inversely correlated, with star-formation dominating the addition of stellar material below M_ and merger accretion events dominating beyond M_. We find mergers have a measurable impact on the whole extent of the GSMF, manifest as a deepening of the `dip' in the GSMF over the next _Gyr and an increase in M_ by as much as 0.01{0.05 dex